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Yb4As3; spin glass; specific heat
Abstract:
Most of the unusual low-T properties of Yb4As3, including a large specific-heat coefficient C(T)/T similar or equal to 200 mJ/K(2)mol, result from the one-dimensional S = 1/2 antiferromagnetism caused by the formation of Yb3+ chains below the charge- ordering transition. On the other hand, large C(T)/T values for non-charge ordered Yb-4(As0.36Sb0.64)(3) and (Yb0.87Lu0.13)(4)As-3 have also been reported. In order to clarify similarities and differences in the low-T specific heat between the 64% Sb- and 13% Lu-doped systems and pure Yb4As3, measurements down to 0.06 K in magnetic fields up to 10T have been performed. The experiments reveal spin-glass freezing around 0.1 and 0.4K for Yb-4(As0.36Sb0.64)(3) and (Yb0.87Lu0.13)(4)As-3, respectively, that also affects their thermodynamic properties at higher temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.
